Fraud prevention for remote transactions

Abstract

A method, apparatus, storage medium, and propagated signal for verifying possession of a user code by a user using a data entry terminal. According to an embodiment, a scramble key is generated. The scramble key is provided to the user and the user prompted to generate an input code by modifying the user code in accordance with the scramble key. The input code is then received from the user. In a further embodiment, it is determined whether the user used the user code to generate the input code, and access by the user of an account associated with the user is permitted only if the user is determined to have used the user code to generate the input code.

What is claimed is:  
     
         1 . A method for verifying possession of a user code by a user using a data entry terminal, the method comprising the steps of: 
 (a) generating a scramble key;    (b) providing the scramble key to the user and prompting the user to generate an input code by modifying the user code in accordance with the scramble key; and    (c) receiving the input code from the user.    
     
     
         2 . The method of  claim 1 , further comprising the steps of: 
 (d) determining whether the user used the user code to generate the input code; and    (e) permitting access by the user of an account associated with the user accordance with the determination of step (d).    
     
     
         3 . The method of  claim 2 , wherein: 
 step (d) comprises the step of determining whether the user used the user code to generate the input code by comparing the input code received from the user to an expected input code, wherein the expected input code is a scrambled input code produced by modifying the user code in accordance with the scramble key; and    step (e) comprises the step of permitting access by the user of the account associated with the user only if the input code matches the expected input code.    
     
     
         4 . The method of  claim 1 , wherein the data entry terminal is a public telephone.  
     
     
         5 . The method of  claim 4 , wherein: 
 said scramble key is a random scramble key generated in response to activation by the user; and    activation by the user comprises the user placing a charge telephone call; and    further comprising the steps of: 
 (d) determining whether the user used the user code to generate the input code; and  
 (e) placing the telephone call and charging the telephone call to an account associated with the user code only if the user is determined to have used the user code to generate the input code.  
   
     
     
         6 . The method of  claim 1 , wherein step (a) comprises the steps of: 
 (1) accessing the user code from a database; and    (2) generating a random difference value for at least one digit of the user code, wherein if the difference value for a digit of the at least one digit is positive then the digit plus the difference value is not greater than 9 and if the difference value for the digit is negative then the digit minus the difference value is not less than 0, wherein said scramble key comprises said random difference values.    
     
     
         7 . The method of  claim 6 , wherein the user code is a personal-identification number (PIN) code.  
     
     
         8 . The method of  claim 6 , wherein step (b) comprises the step of: 
 (1) for at least one digit of the user code, prompting the user to add or subtract the difference value of the scramble key from each of the at least one digits, in accordance with whether the difference value is positive or negative.    
     
     
         9 . An apparatus for verifying possession of a user code by a user using a data entry terminal, the apparatus comprising: 
 (a) means for generating a scramble key;    (b) means for providing the scramble key to the user and prompting the user to generate an input code by modifying the user code in accordance with the scramble key; and    (c) means for receiving the input code from the user.    
     
     
         10 . The apparatus of  claim 9 , further comprising: 
 (d) means for determining whether the user used the user code to generate the input code; and    (e) means for permitting access by the user of an account associated with the user accordance with the determination of means (d).    
     
     
         11 . The apparatus of  claim 10 , wherein: 
 means (d) comprises means for determining whether the user used the user code to generate the input code by comparing the input code received from the user to an expected input code, wherein the expected input code is a scrambled input code produced by modifying the user code in accordance with the scramble key; and    means (e) comprises means for permitting access by the user of the account associated with the user only if the input code matches the expected input code.    
     
     
         12 . The apparatus of  claim 9 , wherein the data entry terminal is a public telephone.  
     
     
         13 . The apparatus of  claim 12 , wherein: 
 said scramble key is a random scramble key generated in response to activation by the user; and    activation by the user comprises the user placing a charge telephone call; and    the apparatus further comprising: 
 (d) means for determining whether the user used the user code to generate the input code; and  
 (e) means for placing the telephone call and charging the telephone call to an account associated with the user code only if the user is determined to have used the user code to generate the input code.  
   
     
     
         14 . The apparatus of  claim 9 , wherein means (a) comprises: 
 (1) means for accessing the user code from a database; and    (2) means for generating a random difference value for at least one digit of the user code, wherein if the difference value for a digit of the at least one digit is positive then the digit plus the difference value is not greater than 9 and if the difference value for the digit is negative then the digit minus the difference value is not less than 0, wherein said scramble key comprises said random difference values.    
     
     
         15 . The apparatus of  claim 14 , wherein the user code is a personal-identification number (PIN) code.  
     
     
         16 . The apparatus of  claim 14 , wherein means (b) comprises means for prompting the user to add or subtract, for at least one digit of the user code, the difference value of the scramble key from each of the at least one digits, in accordance with whether the difference value is positive or negative.  
     
     
         17 . A computer-readable medium having stored thereon a plurality of instructions for verifying possession of a user code by a user using a data entry terminal, wherein the plurality of instructions, when executed by a processor, cause the processor to perform the steps of: 
 (a) generating a scramble key;    (b) providing the scramble key to the user and prompting the user to generate an input code by modifying the user code in accordance with the scramble key; and    (c) receiving the input code from the user.    
     
     
         18 . The computer-readable medium of  claim 17 , wherein said plurality of instructions cause the processor to perform the further steps of: 
 (d) determining whether the user used the user code to generate the input code; and    (e) permitting access by the user of an account associated with the user accordance with the determination of step (d).    
     
     
         19 . The computer-readable medium of  claim 19 , wherein: 
 step (d) comprises the step of determining whether the user used the user code to generate the input code by comparing the input code received from the user to an expected input code, wherein the expected input code is a scrambled input code produced by modifying the user code in accordance with the scramble key; and    step (e) comprises the step of permitting access by the user of the account associated with the user only if the input code matches the expected input code.    
     
     
         20 . A propagated computer data signal transmitted via a propagation medium, the computer data signal comprising a plurality of instructions for verifying possession of a user code by a user using a data entry terminal, wherein the plurality of instructions, when executed by a processor, cause the processor to perform the steps of 
 (a) generating a scramble key;    (b) providing the scramble key to the user and prompting the user to generate an input code by modifying the user code in accordance with the scramble key; and    (c) receiving the input code from the user.